煤层空巷内氮气驱替瓦斯过程数值模拟

Numerical Simulation of Nitrogen Displacing Gas Process in Abandoned Roadway of Coal Seam

为探索煤层空巷内氮气驱替瓦斯过程,了解氮气在驱替煤层空巷内原有气体过程中扩散运动的状态,通过建立巷道建模,利用Fluent软件对氮气在煤层空巷驱替过程中状态进行模拟分析。分析得出在注氮的初始阶段氮气截面呈现线性缓慢扩散,但随着时间的推移,注氮量的增加,注入的氮气与原有空巷内的气体呈现了对流与扩散的状态,形成了氮气完全置换段与混合置换段,并逐步向巷道前方推移。同时结合德通煤业空巷持续注氮驱替瓦斯的工程案例,考察了注氮驱替瓦斯的有效性及稳定性。

In order to explore the process of nitrogen displacing gas in abandoned roadway of coal seam, and understand the state of diffusion motion of nitrogen in the process of displacing gas in the abandoned roadway. The roadway numerical model was established, the software of Fluent was used to simulate and analyze the state of nitrogen during the displacement process. The analysis results show that the displacemnt process of nitrogen is linear and slow diffusion in the initial phase of nitrogen injection. But, with time going by and the increasing of the amount of nitrogen injection, the injected nitrogen and the gas in the original abandoned roadway present convection and diffusion state; it forms the complete displacement of nitrogen and the mixed displacement segment, and is gradually moving forward. Combining with Engineering case of continuous injection of nitrogen to displace gas in abandoned roadway of Detong Coal Mine, the effectiveness and stability of nitrogen displacing gas were investigated.